Telephone switching apparatus



1. N, RtYN'ofns.

TELEPHONE SWITCHING APPARATUS.

APPLICATION FILED NOV. 26,191].

Patented Dec. 2,1919.

- ha ve/770k. John A/ewber/y Reyna/4.;

UNITE STATES sand? or JOHN NEWIBERRY REYNOLDS, 0F GREENWZCH, CONNECTKGU'J, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, 016 NEW YORK, N. Y., A CORPORATION OF NEVJ YORK.

TELEPHONE SWITCHING APFARATUS.

Application filed November (36, 1913,

To all whom it may concern:

Be it known that 1, JOHN NEWBERRY Rar- NOLDS, a citizen of the United States, residing at Greenwich, in the county of F airfield and State of Connecticut, have invented certain new and useful Improvements in lelephone Switching Apparatus, of which the following is a full, clear, concise, and exact description.

This invention relates to switch controlling circuits, and more particularly to circuits for controlling the operation of a line switch of the type used in automatic telephone exchange systems.

The invention has been shown applied to a crossbar line switch essentially similar in structure to the switch disclosed in applicants Reissue Patent No. 14,236, issued December 26, 1916.

The object of this invention is the provision of a simple, reliable and improved circuit arrangement for operating such switch.

In accordance with this object each trunk bar is provided with electromagnetic operating means individual thereto to preselect it for use, and when a trunk is preselected the electromagnetic operating-means of another trunk bar is allotted for subsequent operation.

Also in accordance with this object means are provided for preventing the operation. of'the switching means for extending a calling line to a called line during the time required for the setting of a trunk bar.

In accordance with this object, means are also provided to prevent the operation ofa line bar when the telephone line associated therewith is a called line.

Other'features will appear from the fol lowing description and claims.

For a more complete descriptionof the device reference is now made to the drawing, which shows a perspective view of the switch with parts broken away, and a circuit arrangement for operating the dev ce.

Referring now to the drawing. the line bars 1 arewpivotally mounted in the sides of a frame'(not shown). Each of these line bars is provided at one end with a r ght angular extension 2, through which PIOJGCtS a pivot pin 3. The other end of each bar also. has an angular extension 1 from wh1oh projects a pivot pin 5 received by an openmg. in the frame. Secured to the bars 1,

Specification of Letters Patent.

Patented Dec. 2, Tit/19.

Serial Etc. 208 942.

bars 80, one being provided for each trunk or connecting circuit. These bars are pivot ally mounted by means of pins 1 1 and 15, which extend through openings in the right-- angular extensions 12 and 13 at each end of the trunk bars. Secured to the bars 80, but insulated therefrom and from each other, are the conducting strips 16, 17 and 18. These strips are provided with a plu rality of integral spring contacts 19, 20 and 21, respectively, one set being'provided for each line bar in the switch or for each subscribers line in the group. These sets of springs project from the trunk and line bars at points adjacent to the points of intersection of such bars. Projecting from the extension 13 of each trunk bar is a catch lever 22, normally retained in a retracted position by a spring 23. Pivotally mounted on the frame is a plurality of catches 24:, one for each trunk bar, each catch being arranged to engage and hold a catch lever 22 when its associated trunk bar is rotated in a clockwise direction (as viewed in the drawing) by the armature 66 of a magnet 65.

A shoulder 52, provided on each trunk bar 80, is arranged to engage an insulating pin 53 fastened to a spring 5'4; so that, upon clockwise rotation of the bar to its set or selected position, the pin 53 .opens the normally closed springs 54 and 55 and closes the normally open springs 55, 58 and 54, 57.

A common latch bar 60 is slidably mounted in the supports 61. This bar 60 has a plurality of lugs 62, one for each trunk bar, and they are so arranged that, when a trunk bar is displaced, the catch lever 22 associated with,the displaced trunk bar engages a lug 62, and moves the bar to the left. A. pin 63 of insulating materialis fastened to the latch bar 60 and is arranged to keep the normally closed contact 64 open whenever any one of the trunk bars is displaced.

A shaft 27 is rotatably mounted in e frame in any suitable manner, and rig i'ly fastened to the shaft are the ratchet wheel 28 and contact wipers 32 and 33. A pawl 29, carried by the armature 30 of an electromagnet 31, engages the teeth of the ratchet wheel 28 to rotate the shaft 27 and the wipers secured thereto. Wiper 33 engages a set of contacts 94 in which terminate the Y provided with two windings, a low resistenergized an ture, a c1rcu1t from battery, armature and with ance winding 41v and a high resistance winding 41. Each magnet 40 is also provided with a pivoted armature 42, having 'a right-angular projection 43, ending in a cam member 44. Projecting upward from each line bar and in a position for engagement by its respective cam member 44, is a pin 45 by means of which the line bar may be rotated upon the attraction of the armature 42. Upon further attraction of the armature 42 a shoulder 46 on the member 43 is arranged to engage thepin 5 in such a manner as to force the line bar to the left,

"as viewed in the drawing. Springs 47, 48

are provided for returning the line bar to its normal position. Sets of contacts 49 and 50 are arranged to be operated by a. pivoted armature 51 of the magnet 40. This magnet is so constructed that, when winding 41 is energized armatures 42 and 51 are attracted, and when winding 41 is energized, armature 51 will be attracted and armature 42 will not be, but if the armatures are already attracted, the current through winding 41 will be sufficient to maintain the armatures attracted when the circuit through winding 41' is opened.

It is believed that the invention-will now be better. understood by describing the operation of the switch.

Upon the subscriber at substation A removlng his receiver from the hook, a circuit will be completed from battery, contact 49, left-hand winding of relay 70, conductor 71, telephone apparatus at substation A, conductor 72, right-hand winding of relay 70, contact50 to round. Relay is thereupon d completes, through its armaback contact of relay 75, conductor 74, low resistance winding 41 of magnet 40, conductor 73, armature and front contact of relay 70 to ground. Armatures 42 and 51 are thereupon attracted, armature 51 opening the contacts. 49 and 50 and causing the deenergization of slow relay 70, while armature 42,'through the engagement of cam 44 pin 45, causes the line bar 1 to be rotated. The rotation of this line bar causes the contact terminals 9, 10 and 11 to move downwardly, and places one set the terminals in operative relation to contacts 19, 20 and 21, respectively, of the preselected trunk bar 80. Upon further attraction of the armature 42, the engagement of shoul- .(ler 46 with pin 5 forces the bar 1 to the left,

'21 and 9, conducting strip 6, conductor 71,

telephone apparatus at substation A, conductor 72, conducting strip 7, terminals 10 and 20, conducting strip 17, conductor 79 to ground. Relay 76 thereupon becomes energized and places ground on conductor 81 to cause the test terminal 93 to test busy andto place ground upon the test strip 16 when the trunk bar is released. Upon engagement of terminals 11 and 19, a circuit is completed for the high resistance winding 41 of magnet 40 in series with tri magnet 26, from grounded battery, win ing 41 of magnet 40, conducting strip 8, terminals 11 and 19, conducting strip 16, conductor 84, springs 55, 58, conductor 85, magnet 26 to ground. Magnet 26 thereupon becomes energized and by attracting its armature 24 releases the trunk bar, which is returned to its normal position by spring 23. Trunk bar 80, by returning to its normal position, opens springs 55, 58 and closes springs 55, 54, thereby closing a holding circuit for magnet 40 through the high resistance winding 41 to ground at the armature and front contact of'relay 76. Magnet 40 thereby maintains the line bar 1 in engagement with the trunk bar 80."

When the trunk bar 80 returns to its normal position, terminals of the set which are in engagement with the line terminals remain in contact therewith, due to the flexibility of said terminals. The other sets of terminals, carried by the trunk bar, are rotated in an anti-clockwise direction, as viewed in the drawing, to place them in a position where they will not be engaged by the terminals carried by the bar of the next calling line. The trunk bar, in returning to its normal position, also allows the latch bar 60 to be returned to its normal position by spring 87, and close the contacts 64 to complete a circuit for the pilot relay 75. Relay 75, by attracting its armature, disconnects battery from conductor 74 common to all of the windings 41 of the line bar operat ng magnets, thereb preventing the operation of another line ar until a trunk bar has been displaced. A circuit is closed at the same time for the magnet 65 of the trunk bar next to be selected, through wiper 33, which is now in engagement with 89, conductor 91, contacts 86 to ground. Re-

lay 89 closes at its right-hand armature and front contact 'a circuit for the stepping magnet 31v from grounded battery, right-hand armature and front contact of relay 89, magnet 31, armature to ground. The attraction of armature 30 of the magnet 31 causes,

through the pawl 29, the rotation of theshaft 27 to successively move the, wipers 32 and 33 into engagement with the contacts 93 and 94, respectively. As longas wiper 32 engages test contacts 93. of busy trunk lines upon which ground is impressed at the armature and front contact of relay 7 601' through contacts 57 and 54 if the trunk bar is set, the test relay will be energized and the stepping circuit will be completed, the

' shaft being rotated by the successive energization-and deenergization of the magnet 31, due to the breaking of its circuit by the attraction of its armature 30. When, 'however, the wiper 32 reaches a test contact 93 of an idle trunk, no ground will be thereon and the test relay 89 will become deenergized. The retraction of its right hand armature will open the stepping circuit for magnet 31, thus stopping the shaft 27 with the wiper 33 in engagement with the contact 94 to which the operatin magnet 65 of the idle trunk is connected. gViper 33 now completes the circuit of this magnet 65 of the idle trunk to the contacts 64 so that, upon v the longitudinal movement of the latch bar when the set-trunk bar is seized, the

magnet 65 of this idle t'runkwill become energized and position the trunk bar of this idle trunk in a position for the reception of the next call.

Upon the calling subscriber hanging up his receiver at the termination of the conversation, the circuit for relay 76 is interrupted and the retraction of its armature opens the holding circuit for the magnet 40.

The deenergization of the magnet 40 causes' the retraction of its armature 42, thus releasin the line .bar which is thereupon returne to normal by the springs 47 and 48, carrying therewith the terminals 9, 10 and 11, previously in engagement with the trunk terminals 21,20 and 19.

attract armature 42, but does attract armature 51, which opens contacts 49 and 5.0 so that, when the subscriber A removes his receiver in answering the call, relay remains deenergized as its circuit is open at contacts 49 and 50, and, therefore, winding 41' of the magnet 40 does not become energized to move the line bar into engagement with a displaced trunk bar.

What is claimed is:

1. In combination, two groups of lines, a plurality of switching devices for connecting a line of one groupto an idle line of.

the other group, electromagnets individual to each of said switching devices for preselecting'it for operation, and means operated by the operation of a preselected switching device for energizing one of said electromagnets to preselect' the switching device associated therewith and for selecting another electromagnet 'for successive operation.

2. In combination, incoming and outgoing lines, a switching device comprising two sets of rotatable shafts, the shafts of one set being at-an angle to those of the other, contact terminals of said incoming and outgoing line's carried by the shafts of said sets respectively, means whereby the rotation of a shaft of each set in adefinite order will cause the engagement 'of their respective contacts, electromagnetic operating means individual to each shaft of one set, and means for operating one of said electromagnetic operating means to normally position one of said shafts of one set to engage terminals on any shaft of the other set and to preselect another one of the electromagnetic operating means for successive energlzation.

. 3. In a switch, a plurality of trunk bars,

contacts on said trunk bars, a plurality of means for displacing said line bars, and I means operated when the contacts on the displaced trunk bars are seized bythe contacts on the line bar for preventing the operation of the last-mentioned displacing.

means until another trunk bar is displaced. In witness whereof, I hereuntosubscribe ilrgi zname this 22nd day of November A. D., .ioH'N NEW'BERRY REYNOLDS. 

